Dynamo-electric machine.



G. M. LARSSON.-

DYNAMO ELECTRIC MACHlNE.

Patented Oct. 30, 1917.

, lA/I/E/VTUR H GUS TAF M. LARSSON.

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GUSTAF' LARSSON, OF NEWARK, NEW JERSEY, ASSIGNOR '10 @611 DYNAMO A NDMOTOR COMEANY CGE?OEATION OF NEW JERSEY.

iorne uo-nnncrnrc machine's.

Specification of Letters Patent.

Patented Oct. 30, iei"'r.=

Application filed'necember 12,1913. Serial hlo. 806,132. v

To all whom it/mag concern:

B it k that I, GUs'rAr M. LAnssoN,

a subject of theKing of Sweden, and a resident of Newark, in the countyof Essex and Z State of New Jersey,'have invented-certain new and usefulImprovements in Dyn'anio- Electrie Machines,- of which the following isa specification.

I The present invention relates generally to dynamo-electric machines,and more particularly, though not exclusively, {to the class of machinesusedfor. electric sell starters in automobiles, wherein the machine'runspart of 'the-tlnie as agenerator and part of the time as a motor.

In such and other dynamo-electric Ina chines it is des rahleto employconnnutatrng poles for the purpose of reducing sparkin and it is .alsoadvantageous under certain circumstances to have a compound field, and,

in the particular case under consideration, a differentially woundfield,-1n order that the voltage may remain constant at differentspeeds.-

In the priorart of dynamo-electric Inachines it has been the practice tohave a separate coil aroundthe commutating pole in series. with thearmature. This requires more wire than is actually needed and more spacethan is usually available.

The object of the present invention is to redu e the amount of wire usedin machines of this character.

To this end the invention consists of a dynamo-electricmachinecomprising an armature; and a field consisting or main poles and one ormore coinniutating poles,together with a field windingin series with thearmature through which amagnetic field is gen erated. in the main polesand having a common coilsurrounding one main pole and the commutatingpole with a single loop.

In case it is desired t'o'have a compound wound machine, the'fie'ld willhave an ad '45 .ditional or main windingin shun't with the armature, thecoils of WlllCll surround the 'tnai n poles only. In that event theseries -wiildins; mayl be considered an auxiliary winding andltakestheform, of a common coil surroundingpn'e mam pole and the commutating polewith a single'loop.

In-- order to obtain the proper space for housing the coils and in orderto. reduce the size of the machine asmuch as possible, the

body/portiongof one or the main zioles he circuinferentially opposite tothe other main pole, while said other main pole has a normal bodyportion circumferentially opposite to .the first main pole. Tl1e facesof said main poles are nevertheless 'symmetri sally arranged withrespect .to each other.

tween which main poles the. commutating' pole 1s interposed, 1s undercuton the slde' Between these-two mainpoles an inter-pole is located whosebody "portion springs'frorn a point adjacent to the normalbodypor tionof the second main pole-but whose face portion extends toward'theundercut portion of the first inain pole soias to have its facesubstantially equidistant from the two main pole faces. Bythis means agreater coll space is aliorded betweenthe interpole and the undercutportionof the-first inain pole than between the interpole and the normalportion of the second nialn pole The result is that ample room isafforded for the Various coils within avery small compass.

Fig. '2 is a substantiallyv horizontal sectional view on the line 22 ofFig. l.

Fig. 3 shows a preferred'form of Wiring. Similar characters of referenceindicate corresponding parts in the several views.

.the uaide rcutportion of one main pole is disposed circumferentiallyopposite t the normal portion of the other main pole. The result is thatthe pole face of each pole appears distortediwit'h respect to its ownbody portion. 8 is, an interpole here serving as coinmutating pole, thebody portion 11 The field is preferably constructed l'ola greater coilspace is'afli'orded between the interpole and the undercut portion ofone main pole than between the mterpole and the normal portion of theother mam pole.

The field winding may consist of a coil 6,

tl rough which the magnetic field is gen erated in the main poles,which, as shown in Fig. 3, is in series with the armature indicated at 7by means of the commutator 13 and brushes 14. This coil 6 surrounds botha mam pole and the mterpolepound wound construction employed, anadditional coil as 5 may be employed which surrounds the mam pole onlyand is m shunt with the armature, as indicated in Fig. 3.

The two windings 5 and (3 may be arranged electrically in various ways.One winding may reinforce the other or the two Windingsmay oppose eachother.

What is claimed, is:

1. In a dynamo-electric machine, two

' main poles the body portion of one of which is undercut on one side,and said other main pole having a normal body portion circumferentiallyopposite to the undercutside ot' the first main pole, the faces of saidmain poles being nevertheless synnnctrically arranged with respect toeach other, and an interpolc whose body portion springs from a pointadjacent to the normal body portion of the second main pole and havingits pole face extending toward the undercut portion of the first mainpole-so as to have its face substantially equidistant from the two mainpole faces, whereby a greater coil space is afforded between theinterpole and the undercut'portion of the first main pole than betweenthe intcrpole and the normal portion of the second main pole.

2. In a dynamoelect1'ic machine, a field member comprising: a pluralityof main poles the faces of which are symmetrically arranged with respectto each other, and

the body portion of each of which is normal on one side and undercut toa greater extent on-the other side, so that each pole face appearsdistorted with respect toits own body portion, the normal portion of onemain pole being arranged circumferentially op- If a com-* posite to'theundercut portion of the othermain pole, vand an inter-pole, whose bodyportion springs from a point adjacent to the normal portion: of one ofsaid main pole-a and having its pole face extending toward the undercutportion of the other main pole so as to have its face substantiallyequidistant from the two main polefaces, whereby a greater coil space isafforded between the interpole and the undercut portion of onei'nain-pole than between the in-, terpole and the normal portion of theother main pole.

3. In a dynamo-electrie machine, two main poles the body portion of bne'of which is undercut on oneside and said other mail pole ha ing a normalbodv portion circurn ferentially opposite to the undercut side of thefirst main'pole, the faces of saidmain poles being neverthelesssymmetrically arranged with rcspcct'to each other, an inlerpole whosebody portion springs from a point adjacent to the nornnil body portionof the second main'pole and having its pole face extendingtoward. theundercut portion of the first mainpolc so as to have its facesubstantially equidistantfrom the two main pole faces, whereby a greatercoil space is afforded between the interpole and tlieundercut portion ofthe first main polo v than between the interpole and the normalportion-of the second main pole, a. coil sur-- rounding a main pola andpassing between the main pole and the inlerpole, and a 500 ond coilsurrounding both a main pole and the inter-pole.

4;. In a dynamo-electric machine, a field member comprising: a pluralityof main poles the faces. of which are symmetrically arrangedwith respectto each other, and the body portion of each of which is normal on oneside and undercut to a greater extent on the other side, so that eachpole face appears distorted. with respect to its own body portion, thenormal portion of one main pole being arranged circmnfercntiallyopposite to the undercut portion of the other main pole, an interpole,whose body portion springs from. a point adjacent to the normal portionof one of said main poles, and having its pole face extending toward theunderci-it portion of the other main pole so as to have its facesubstantially equidistant from the two main pole faces, whereby 2greater coil space is afforded between the .nterpole and the undercutportion of one main pole than between the interpole and the normalportion of the other main pole, a coil surrounding each main pole andpassing between the main and inter-poles, and a second coil surrolmdingboth a main pole and an intcr ')ole.

Signed at Belleville, in the county of- ICssex-and State of New Jersey,this Sth day of December, A. D. 1913.

GUSTA F MAURITZ LARSSON.

Witnesses A. Bonnonois, J. GRAN.

